Grant County Soil Data
Grant County, South Dakota
USDA SSURGO / PHZMAvg pH
7.1
Texture
Gravelly loam
Drainage
Excessively drained
Organic Matter
3.9%
Hydrologic Group
A
Data Story
About Soil in Grant County, South Dakota
Gravelly Loam and Alkaline Soil Identity
Grant County soil features a gravelly loam texture and belongs to the Entisols order, indicating relatively young geologic development. Its average pH of 7.14 is slightly more alkaline than the state average of 7.05 and significantly higher than the national median of 6.5.
A Silt-Heavy Composition for Grant County
The soil contains 41.6% silt, 35.0% sand, and 23.4% clay, creating a versatile but coarse-leaning profile. This mix provides moderate workability while ensuring that roots can penetrate easily through the gravelly loam structure.
Strong Organic Matter Boosts Potential
With 3.93% organic matter, the county surpasses the South Dakota average of 3.75% and nearly doubles the national average of 2.0%. The available water capacity of 0.188 in/in ensures that crops have a steady reservoir during dry spells.
Rapid Drainage for Resilient Foundations
The soil is classified as excessively drained and belongs to hydrologic group A, meaning water moves through it very quickly. This high permeability is ideal for building foundations but requires careful irrigation management for thirsty crops.
Hardy Options for Zone 4b
Located in hardiness zone 4b, Grant County is perfect for cold-tolerant vegetables and perennial fruits like apples. The high soil score of 63.5 suggests a productive environment for any gardener willing to start their seeds early.
Soil Composition
Soil pH
Soil Series
Detailed soil series data not yet available for this county.
Hydrologic Group
Group A — Low Runoff
Sandy, well-drained soils with high infiltration rates. Water moves quickly through the soil profile. Lowest runoff potential when thoroughly wetted.
Drainage Class
Excessively drained
Water is removed very rapidly. Very sandy or gravelly soils with little water retention.
Soil Profile
Dominant texture: Gravelly loam
Typical soil profile. Actual depths vary by location.
USDA Soil Orders
Soil Amendment Products
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Browse Soil AmendmentsFrequently Asked Questions
What type of soil does Grant County have?
Grant County's soil is classified as Gravelly loam. This indicates the relative proportions of sand, silt, and clay — 35% sand, 42% silt, and 23% clay. Loamy soils hold moisture well and support a wide range of plants.
Is Grant County's soil acidic or alkaline?
Grant County's soil has a pH of 7.1, which is near neutral. This range is ideal for most garden plants and field crops.
What is the drainage class for Grant County?
Grant County has a dominant drainage class of "Excessively drained." Moderate drainage allows adequate moisture retention while still permitting excess water to drain over time.
What crops or plants grow well in Grant County's soil?
Based on Grant County's Gravelly loam texture, pH of 7.1, and Excessively drained, the soil is well suited for drought-tolerant crops and native grasses, row crops and vegetable gardens.
What USDA soil order is found in Grant County?
Grant County's dominant soil order is Entisols. Entisols are recently formed soils with little to no horizon development. They are common on floodplains, steep slopes, and sandy deposits.
Soil & Planting Advisory: Grant County
Soil Verdict
Grant County is in USDA hardiness zone 4b, a cold climate zone. where winter lows can reach -25°F. Soils here experience deep freeze cycles that can disrupt structure, kill shallow roots, and slow microbial activity for months each year.
Planting Guidance
Focus on cold-hardy perennials, native grasses, and conifers. The short growing window favors plants with low heat requirements. With extreme winter lows, any marginally hardy plants need heavy mulch and wind protection. Always match plant selections to the specific microclimate of your property — low spots, slopes, and wind exposure can shift effective hardiness by half a zone.
Soil Implications
Deep winter freezing can create soil heaving that pushes shallow-rooted plants out of the ground; add 3-4 inches of organic mulch each fall. Soil drainage is critical — frozen, waterlogged soil kills roots faster than cold alone. When soil temperatures drop below freezing, microbial nitrogen cycling stops; spring fertilization is more effective than late-fall application.
Regional Context
Grant County closely matches the South Dakota average hardiness conditions. The zone range of 4a-4b within the county means soil and planting decisions should account for local elevation and topography.
Planning your lawn? View lawn care data for Grant County on LawnByCounty.com →
Other Counties in South Dakota
Soil data sourced from USDA SSURGO via Soil Data Access. Data is informational only and should not be used as a substitute for on-site soil testing. Contact your local NRCS office for site-specific soil information.